2:11 p.m. on February 8, 2010 (EST)
GooGone unfortunately is a mix of chemicals. So be really careful with it, and even more so with GoofOff. Always try a small amount on a part of the tent, clothes, or whatever you need to clean (or a small swatch of the material that you cut off) in a hidden spot or a spot where it won't matter. If it is a rope on which your life will depend (f_klock's tree-climbing rope or a rock or ice climbing rope), be extremely careful about any cleaning fluids.
As an example of what can happen, I had some pine sap on a tent. I took a section of an old tent and tested Goof-Off on it - it dissolved the nylon. I also tried GooGone - same result (even though the container says nylon is ok).
The GooGone bottle says:
Do not use on silk, satin, wool, velvet, leather, suede, rubber, latex, or vinyl. May dull some types of plastics. DO NOT MIX WITH OTHER CHEMICALS.
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Contains Petroleum Distillates CAS# 64741-65-7, d-Limonene CAS# 5989-27-5, Orange Oil CAS# 8008-57-9, and Tripropylene Glycol Methyl Ether CAS# 25498-49-1
GoofOff says:
For use on: Nylon, polypropylene, and wool carpets; fully cured varnished and oil-base painted surfaces, vinyl baseboard, laminated countertops, vinyl floors, solid vinyl upholstery, all metals, glass, brick, wood, concrete, grout, vinyl tops, fiberglass, most fabrics.
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Contains: Acetone, Xylene, Ethylbenzene, Butyl Carbitol, Petroleum distillates, and toluene
Basically, read the labels completely, test out on small samples, and do it outdoors, no matter what you are using.